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nfsd4: allow 4.0 clients to change callback path

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The rfc allows a client to change the callback parameters, but we didn't
previously implement it.

Teach the callbacks to rerun themselves (by placing themselves on a
workqueue) when they recognize that their rpc task has been killed and
that the callback connection has changed.

Then we can change the callback connection by setting up a new rpc
client, modifying the nfs4 client to point at it, waiting for any work
in progress to complete, and then shutting down the old client.

Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
This commit is contained in:
J. Bruce Fields
2010-03-07 23:39:01 -05:00
parent 2bf23875f5
commit 4b21d0defc
3 changed files with 24 additions and 14 deletions
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29
fs/nfsd/nfs4callback.c
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@ -457,9 +457,8 @@ static int max_cb_time(void)
/* Reference counting, callback cleanup, etc., all look racy as heck.
* And why is cl_cb_set an atomic? */
int setup_callback_client(struct nfs4_client *clp)
int setup_callback_client(struct nfs4_client *clp, struct nfs4_cb_conn *cb)
{
struct nfs4_cb_conn *cb = &clp->cl_cb_conn;
struct rpc_timeout timeparms = {
.to_initval = max_cb_time(),
.to_retries = 0,
@ -481,7 +480,7 @@ int setup_callback_client(struct nfs4_client *clp)
if (!clp->cl_principal && (clp->cl_flavor >= RPC_AUTH_GSS_KRB5))
return -EINVAL;
if (cb->cb_minorversion) {
args.bc_xprt = clp->cl_cb_conn.cb_xprt;
args.bc_xprt = cb->cb_xprt;
args.protocol = XPRT_TRANSPORT_BC_TCP;
}
/* Create RPC client */
@ -491,7 +490,7 @@ int setup_callback_client(struct nfs4_client *clp)
PTR_ERR(client));
return PTR_ERR(client);
}
clp->cl_cb_client = client;
nfsd4_set_callback_client(clp, client);
return 0;
}
@ -548,14 +547,13 @@ void do_probe_callback(struct nfs4_client *clp)
/*
* Set up the callback client and put a NFSPROC4_CB_NULL on the wire...
*/
void
nfsd4_probe_callback(struct nfs4_client *clp)
void nfsd4_probe_callback(struct nfs4_client *clp, struct nfs4_cb_conn *cb)
{
int status;
BUG_ON(atomic_read(&clp->cl_cb_set));
status = setup_callback_client(clp);
status = setup_callback_client(clp, cb);
if (status) {
warn_no_callback_path(clp, status);
return;
@ -645,18 +643,32 @@ static void nfsd4_cb_done(struct rpc_task *task, void *calldata)
}
}
static void nfsd4_cb_recall_done(struct rpc_task *task, void *calldata)
{
struct nfs4_delegation *dp = calldata;
struct nfs4_client *clp = dp->dl_client;
struct rpc_clnt *current_rpc_client = clp->cl_cb_client;
nfsd4_cb_done(task, calldata);
if (current_rpc_client == NULL) {
/* We're shutting down; give up. */
/* XXX: err, or is it ok just to fall through
* and rpc_restart_call? */
return;
}
switch (task->tk_status) {
case -EIO:
/* Network partition? */
atomic_set(&clp->cl_cb_set, 0);
warn_no_callback_path(clp, task->tk_status);
if (current_rpc_client != task->tk_client) {
/* queue a callback on the new connection: */
nfsd4_cb_recall(dp);
return;
}
case -EBADHANDLE:
case -NFS4ERR_BAD_STATEID:
/* Race: client probably got cb_recall
@ -705,8 +717,7 @@ void nfsd4_destroy_callback_queue(void)
destroy_workqueue(callback_wq);
}
void nfsd4_set_callback_client(struct nfs4_client *clp, struct rpc_clnt
*new)
void nfsd4_set_callback_client(struct nfs4_client *clp, struct rpc_clnt *new)
{
struct rpc_clnt *old = clp->cl_cb_client;